This application relates to clamping devices and more particularly to clamping devices for use on presses. The invention is particularly applicable for use in clamping dies in a press, and will be particularly described with respect thereto. However, it will be recognized that the invention has broader applications and may be used for clamping other things.
Clamping devices of a known type for use in presses include an elongated clamping rod mounted for rotatable and axial movement in a bore formed in a housing. One end of the rod has a clamping member thereon exteriorly of the bore and the other end portion has an adjustment nut for moving the rod into final clamping engagement. One such clamping device of this type is shown in U.S. Pat. No. 3,111,895 to Kraft, and particularly FIG. 6 of that patent. In previous arrangements of the type described, the rod must undergo considerable axial movement before it is in a clamping position. In previous arrangements, fluid pressure was relied upon for a major portion of this axial movement. The use of fluid pressure required that the rod be manufactured with close tolerances for a tight fit within the bore, and seals are required so that a portion of the rod can act as a piston when fluid pressure is introduced into the bore. Final clamping movement of the prior devices was accomplished by rotating a nut threaded onto the other threaded end portion of the rod. Movement of the rod with the threaded nut arrangement is very limited in previous devices.
It would be desirable to construct a clamping device of the type described which maintains maximum axial movement while eliminating the need for seals and fluid pressure to accomplish maximum axial movement.